I don't see any rust- but the ad doesn't mention, so I'd be underneath it to check. Just becasue its in CA now doesn't mean that's the only place it has ever been.

Consider the interior to be in bad shape, and if you plan on replacing with boneyard parts- I'd call around and see what is out there. (I bought our 190 with the idea that I'd change out one of the seats and that was nearly 10 years ago. This swap hasn't happened because I can't find a donor with interior parts in better condition than what I've got. And finding an old benz around here in a yard is impossible- but there's plenty of 90s Kias!)

Also, ask your friend what he's expecting from the car. I have met more than a few people who are mistakenly under the impression that all diesels get 50 mpg- and that car might only see half that figure occasionally according to conversations I've had with sd owners at the pumps. (please don't flame me if your 300sd got almost 30mpg on a downhill run with a 60 mph wind to your back- I'm just saying I usually hear figures like 18 to 25 mpg.)

Lastly, other members may have better insight but I think the price is a little steep for a car with windows, seats, radio, AC and etc. that are broken and don't work and an interior that is kaput. I'd make an offer that would allow you to have some money to replace those parts and get it in good working order.

Best of luck!